scholarly journals Large Eddy Simulations of gaseous flames in gas turbine combustion chambers

2012 ◽  
Vol 38 (6) ◽  
pp. 782-817 ◽  
Author(s):  
L.Y.M. Gicquel ◽  
G. Staffelbach ◽  
T. Poinsot
Keyword(s):  
Gas Turbine ◽  
Large Eddy Simulations ◽  
Combustion Chambers ◽  
Large Eddy ◽  
Gas Turbine Combustion

Large-Eddy Simulations as a Design Tool for Gas Turbine Combustion Systems

AIAA Journal ◽  
2006 ◽  
Vol 44 (4) ◽  
pp. 674-686 ◽  
Author(s):  
S. James ◽  
J. Zhu ◽  
M. S. Anand
Keyword(s):  
Gas Turbine ◽  
Design Tool ◽  
Large Eddy Simulations ◽  
Large Eddy ◽  
Gas Turbine Combustion ◽  
Combustion Systems

LES of Swirling Flows in Gas Turbine Combustion Chambers

2004 ◽  
Author(s):  
Bogdan Gherman ◽  
Robert-Zoltan Szasz ◽  
Laszlo Fuchs
Keyword(s):  
Gas Turbine ◽  
Swirling Flows ◽  
Large Eddy Simulations ◽  
Combustion Chambers ◽  
Axial Distribution ◽  
Swirl Angle ◽  
Large Eddy ◽  
Air Mixing ◽  
Inlet Conditions ◽  
Gas Turbine Burner

The flow and mixing in a swirl-stabilized gas-turbine burner is studied by Large Eddy Simulations (LES). Each swirler has a different mass flux and swirl angle. The interaction between neighbouring jets is studied, co-rotating and counter rotating jets are considered. Another issue of importance is related to the jet inlet conditions (e.g. axial distribution and levels of turbulence). In addition to the flow field (using LES) we present results related to fuel/air mixing under different conditions. We show that the LES results can resolve several issues related to the burner that cannot be accounted for by the standard RANS computations.

High Resolution Large Eddy Simulations to Evaluate Turbulence Properties Within a Real Helicopter Engine Combustor

2018 ◽  
Author(s):  
Charlie Koupper ◽  
Jean Lamouroux ◽  
Stephane Richard ◽  
Gabriel Staffelbach
Keyword(s):  
Gas Turbine ◽  
Turbulence Intensity ◽  
Numerical Scheme ◽  
Mesh Refinement ◽  
Large Eddy Simulations ◽  
Scale Model ◽  
Large Eddy ◽  
Set Up ◽  
High Level ◽  
The Impact

In a gas turbine, the combustor is feeding the turbine with hot gases at a high level of turbulence which in turns strongly enhances the heat transfer in the turbine. It is thus of primary importance to properly characterize the turbulence properties found at the exit of a combustor to design the turbine at its real thermal constraint. This being said, real engine measurements of turbulence are extremely rare if not inexistent because of the harsh environment and difficulty to implement experimental techniques that usually operate at isothermal conditions (e.g. hot wire anemometry). As a counterpart, high fidelity unsteady numerical simulations using Large Eddy Simulations (LES) are now mature enough to simulate combustion processes and turbulence within gas turbine combustors. It is thus proposed here to assess the LES methodology to qualify turbulence within a real helicopter engine combustor operating at take-off conditions. In LES, the development of turbulence is primarily driven by the level of real viscosity in the calculation, which is the sum of three contributions: laminar (temperature linked), turbulent (generated by the sub-grid scale model) and artificial (numerics dependent). In this study, the impact of the two main sources of un-desired viscosity is investigated: the mesh refinement and numerical scheme. To do so, three grids containing 11, 33 and 220 million cells for a periodic sector of the combustor are tested as well as centred second (Lax-Wendroff) and third order (TTGC) in space schemes. The turbulence properties (intensity and integral scales) are evaluated based on highly sampled instantaneous solutions and compared between the available simulations. Results show first that the duration of the simulation is important to properly capture the level of turbulence. If short simulations (a few combustor through-times) may be sufficient to evaluate the turbulence intensity, a bias up to 14% is introduced for the turbulence length scales. In terms of calculation set-up, the mesh refinement is found to have a limited influence on the turbulence properties. The numerical scheme influence on the quantities studied here is small, highlighting that the employed schemes dissipation properties are already sufficient for turbulence characterization. Finally, spatially averaged values of turbulence intensity and lengthscale at the combustor exit are almost identically predicted in all cases. However, significant variations from hub to tip are reported, which questions the pertinence to use 0-D turbulence boundary conditions for turbines. Based on the set of simulations discussed in the paper, guidelines can be derived to adequately set-up (mesh, scheme) and run (duration, acquisition frequency) a LES when turbulence evaluation is concerned. As no experimental counterpart to this study is available, the conclusions mainly aim at knowing the possible numerical bias rather than commenting on the predictivity of the approach.

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